How to Change Color of the Logo Area which is White

Go in to the editor in your wp-admin panel and find the code on the style sheet

.my-head {
	margin:10px auto 0 auto;
	max-width:980px;
	padding:0;
 	background:#ffffff;
	border-top:2px solid #efefef;
	border-bottom:1px solid #cdcdcd;
	box-shadow: 0 3px 3px #dedede;
	-moz-box-shadow: 0 3px 3px #dedede;
	-webkit-box-shadow: 0 3px 3px #dedede;
	-o-box-shadow: 0 3px 3px #dedede;
}

Replace the background color in the style sheet ( #ffffff ) to the color you desire.

You can find any color you want at https://www.w3schools.com/tags/ref_colorpicker.asp